Overview
This lecture discusses methods for mapping internal computer names to IP addresses in a network, focusing on host files, local DNS servers, and directory services.
Mapping Internal Computers to IP Addresses
- DNS servers can map internal computers to IP addresses, allowing name-based access instead of using numeric IPs.
- Mapping improves usability by letting users reference computers by hostname.
Host Files
- A host file is a local file that contains static mappings of IP addresses to hostnames.
- On Linux, the host file usually maps 127.0.0.1 to "localhost," referencing the current computer.
- "Localhost" is used to access services running on the local machine.
- Modifying the host file can redirect hostnames (like www.google.com) to other addresses, but this only affects the local computer.
- DNS queries check the host file before contacting a DNS server.
- Using host files for many computers is not scalable, as changes must be made to each device manually.
Local DNS Servers
- A local DNS server centrally stores mappings of hostnames to IP addresses for an organization.
- Network settings on all computers must be configured to use the organization's DNS server.
- This is more scalable than using host files for each computer.
Directory Services Integration
- DNS can be integrated with directory services (e.g., Active Directory, LDAP) that manage user and machine information centrally.
- With integration, machine-to-IP mappings are added to DNS automatically, removing the need for manual entry.
Key Terms & Definitions
- Host File — A file on a computer that maps hostnames to IP addresses manually.
- Localhost — The hostname that refers to the local machine, usually mapped to 127.0.0.1.
- DNS (Domain Name System) — A system that translates hostnames to IP addresses.
- Directory Service — A centralized database for user and device information, such as Active Directory or LDAP.
Action Items / Next Steps
- Review how to edit host files on your operating system.
- Research setting up a local DNS server for your network.
- Learn about integrating DNS with directory services like Active Directory or LDAP.